HE 1327-2326
HE1327-2326, discovered in 2005 by Anna Frebel and collaborators, was the star with the lowest known iron abundance until SMSS J031300.36−670839.3 was discovered. The star is a member of Population II stars, with a solar-standardised iron to hydrogen index, or metallicity, of −5.6. The scale being logarithmic, this number indicates that its iron content is 1/400,000 that of the Earth's sun. However, it has a carbon abundance of roughly one-tenth solar, and it is not known how these two abundances can have been produced/exist simultaneously. Discovered by the Hamburg/ESO survey for metal-poor stars, it was probably formed during an age of the universe when the metal content was much lower. It has been speculated that this star is part of the second generation, born out of the gas clouds which were imbued with elements such as carbon by the primordial Population III stars.
